The image, taken on July 7, 2015, is the closest image of Pluto. The space probe New Horizons was just under 5 million miles from the dwarf planet. The white heart-sized area is about 1,200 miles across and scientists don't exactly know what it means.

"The next time we see this part of Pluto at closest approach, a portion of this region will be imaged at about 500 times better resolution than we see today," said Jeff Moore of NASA’s Ames Research Center. "It will be incredible!"